1oow
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(New page: 200px<br /><applet load="1oow" size="450" color="white" frame="true" align="right" spinBox="true" caption="1oow, resolution 2.00Å" /> '''The crystal structur...)
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Revision as of 20:57, 20 November 2007
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The crystal structure of the spinach plastocyanin double mutant G8D/L12E gives insight into its low reactivity towards photosystem 1 and cytochrome f
Overview
Plastocyanin (Pc) is a copper-containing protein, which functions as an, electron carrier between the cytochrome b(6)f and photosystem 1 (PS1), complexes in the photosynthetic electron transfer (ET) chain. The ET is, mediated by His87 situated in the hydrophobic surface in the north region, of Pc. Also situated in this region is Leu12, which mutated to other amino, acids severely disturbs the ET from cytochrome f and to PS1, indicating, the importance of the hydrophobic surface. The crystal structure of the Pc, double mutant G8D/L12E has been determined to 2.0 A resolution, with a, crystallographic R-factor of 18.3% (R(free)=23.2%). A comparison with the, wild-type structure reveals that structural differences are limited to the, sites of the mutations. In particular, there is a small but significant, change in the hydrophobic surface close to His87. Evidently, this leads to, a mismatch in the reactive complex with the redox partners. For PS1 this, results in a 20 times weaker binding and an eightfold slower ET as, determined by kinetic measurements. The mutations that have been, introduced do not affect the optical absorption spectrum. However, there, is a small change in the EPR spectrum, which can be related to changes in, the copper coordination geometry.
About this Structure
1OOW is a Single protein structure of sequence from Spinacia oleracea with CU as ligand. Full crystallographic information is available from OCA.
Reference
The crystal structure of the spinach plastocyanin double mutant G8D/L12E gives insight into its low reactivity towards photosystem 1 and cytochrome f., Jansson H, Okvist M, Jacobson F, Ejdeback M, Hansson O, Sjolin L, Biochim Biophys Acta. 2003 Dec 8;1607(2-3):203-10. PMID:14670610
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